Feeder verification with a camera

ABSTRACT

Method for component verification during operation of a component placement machine ( 101 ) having a series of feeder slots ( 103 ) for holding component feeders ( 104 ) with feeder markers, each feeder marker carrying a unique feeder ID, wherein each feeder slot ( 103 ) has a unique slot ID ( 208 ). On an image taken with a camera of the feeder slots, image analysis is performed to check whether the actual feeders in the slots corresponds to those feeders that are intended to be placed in these slots.

FIELD OF THE INVENTION

The present invention relates to the monitoring of the configuration ofcomponent feeders on a component placement machine, for example forelectronic components.

BACKGROUND OF THE INVENTION

For electronic board assembly, automated component placement can reachvery high speed up to tens of thousands of surface mounts of componentsper hour. These components are typically supplied by component vendorsas taped reels of components which are loaded onto individual feederswhich then are mounted in corresponding feeder slots on the machine.These reels of components may be loaded onto the feeders at a specialloading unit, for example in a stock room, after which the loadedfeeders are placed in the feeder slots.

Component placement machines can have more than 100 feeder slots eachaccessible by a picking mechanism that picks individual components fromthe feeders in the slots and places them in particular predeterminedlocations on a printed circuit board. For application flexibility, eachfeeder and slot is generally constructed to be compatible with manydifferent components.

The physical arrangement of components, feeders and slots must be inaccordance with the expected arrangement as programmed in the machine.Any error in the arrangement can cause a corresponding error in theplacement of components on the board. In a high volume, low mixmanufacturing environment, a component loading error can produce a highnumber of defective printed circuit boards in a short period of time. Ina low volume, high mix environment the chance of component loading errorincreases because of frequent feeder manipulation for product changeover.

In order to eliminate loading errors, it is known to place bar codelabels on individual feeders and slots for manual scanning to controlthat the right components indeed are placed in the right slots accordingto a so called device list, which contains a listing of the slots andthe components that are expected in the different slots. This procedureis carried out, before the machine begins its operation.

Often, component placement machines are not born with sufficient controlmechanisms to assure the feeding of correct components as desired by theuser of these types of machines. Different solutions have been suggestedwhere additional equipment is provided from a producer different thanthe producer of the machine and post-mounted on the machine. For suchpost-mounting, certain conditions in connection with the machines, asthe mechanical structure, have to be taken into account. Often, the taskis not to find the optimum solution generally, but to find the optimumsolution under the given circumstances, that is to say to find theoptimum solution for a given mechanical structure of the componentplacement machine. For example, some component placement machines havefeeders on a platform or table that moves with respect to the pick-upsystem while others have a stationary table and a moving pick-up system.The control solutions are typically different for these two differenttypes of machines.

A machine with an integrated control system is disclosed in Japanesepatent application JP 2000 0223923 by Akira Tsunoda. This system isdesigned for a feeder system produced by Yamaha Motor Co Ltd, where acamera is mounted on the pick-up device and images the feederidentification close to the position where components are picked up. Thesystem is used after installation of the feeders and before start of theindustrial process for fabrication of the product. For use, the pick-upmechanism moves along the feeder table and images one feeder ID afterthe other, until all feeder IDs have been scanned. If a mistake isobserved by the system, an alarm is sent to the operator for correctionof the set-up. If the set-up is corrected, the system is used again forthe control until the control reveals a correct installation of thefeeders. This system has a number disadvantages. Firstly, this system isonly suited for machines with sufficient space for mounting of a cameraon the moving pick-up mechanism. Secondly, the feeder ID has to beplaced relatively precisely in the vicinity of the pick-up region inorder that the camera can image the ID. For a system integrated in aspecial machine, this is adaptable; however, several existing feedermachines do not have space at the pick-up region for mount of an ID.Therefore, this system is not suited for post-mounting. Thirdly, thissystem utilizes the machine information of the slot positions. As themachine is born with the control system, this utilizing is possible;however, such position information is usually not available forpost-mounted systems. Fourthly, the procedure is performed before thestart of the machine and in case of determined mistakes repeated beforethe start of the machine. Thereby, expensive time is wasted before theproduction start. Fifthly, if a number of feeders are placed wrongly inthe machine, the time used for replacement of the feeder and asuccessive scan is multiplied. This can be understood from thefollowing: a first error will be detected for the first wrongly placedfeeder, after which a replacement has to be performed and a new scan hasto be performed revealing the next wrongly placed feeder. This adds upto a long time before the machine is ready for operation. It would bedesirable to provide a system not having these disadvantages.

A post-mounted control system has been disclosed in U.S. Pat. No.6,027,019. In this system, two scanners are adapted to monitor thearrangement of slot markers and feeder markers in the machine while themachine is in operation. The slot marker and feeder marker are thencompared with data in a device list. Such a control system is onlysuitable for existing machines, where the table is moveable while thepick up is stationary, because in many existing machines with movablepick-up systems, not enough space is left on the pick up for mounting ascanner on the pick-up. This system as described in U.S. Pat. No.6,027,019 has another disadvantage in not being able to detect feederswith wrong components before the machine is started. An eventual erroris first detected, after the first component has been picked up. If acomponent is wrong, expensive time is wasted until the machine isstopped and rearranged. A third disadvantage has also been observed forthis system. As the table is moved, problems with reading of the feederID may occur in situations where a component from a special feeder ispicked up from one edge of the feeder such that the feeder position isdifferent than if the component would be picked up from the centre ofthe feeder.

For machines with stationary feeder platforms, a system is known, whereeach feeder is equipped with a transponder that is connected with thefeeder by a chain. The transponder is inserted in a corresponding arrayplatform behind the feeder for manual check whether the feeder is in theright slot. However, also this system has a drawback in not being ableto prevent a misplacement of the transponder. The latter is due to thefact that feeders may be rather slim with the result of a hardlydiscernible correct position of two adjacent feeder positions in theplatform.

For existing machines, no control solution has hitherto been proposedfor taking into account the situation of the so-called splicing when afeeder only has a few components left on a tape. During splicing, theempty reel is taken out of the feeder without removing the remaining fewcomponents on the tape in the feeder. The tape with the remaining fewcomponents is then fastened—spliced—to a new tape with components rolledon a new reel, which then is inserted into the feeder. The advantage isthat reels can be exchanged without having to exchange the feeder orstop the operation of the machine. However, no system has hitherto beenprovided to control whether a tape with correct components has beenspliced to the tape with the remaining few components.

SUMMARY OF THE INVENTION

It is the purpose of the invention to provide a cheap, fast and reliablesystem suitable for post-mounting and a method for monitoring theconfiguration of component feeders on a component placement machine,where the system and method are independent of whether the machine has amovable platform or a moveable pick-up. Advantageously, the inventionshall also be extendable to take into account the situation of splicing.

This purpose is achieved by a method for component verification inconnection with operation of a component placement machine having aseries of feeder slots for holding component feeders with feedermarkers, each feeder marker carrying a unique feeder ID, wherein eachfeeder slot has a unique slot ID, wherein the method comprisesdetermining the actual feeder IDs carried by the actually installedfeeders in the series of feeder slots and using this information incomparison with stored configuration information to check forconfiguration errors, in addition to providing at least one camera forproviding an image spanning over the series of feeder slots, providingthe image and performing image analysis on the image for determining theactual feeder IDs carried by the actually installed feeders in theseries of feeder slots. In order to provide image analysis, differentkinds of image analysis systems for digital images exist commercially.

The method according to the invention has a number of advantages. It maybe implemented on existing placement machines, which is an importantcriterion. A camera, for example with a CCD (charge coupled device)detector, may be installed stationary at an appropriate location withoptics that images all feeder slots with a suitable resolution. A mountof a camera on the pick-up head is thereby avoided. Alternatively,especially if a large number of feeders are used, a number of camerasmay be provided, where each camera images a series of feeders and where,finally, an image for analysis is produced as a combined image from theimages from this number of cameras. Such image addition is knownaccording to prior art in different application fields. By imaging allfeeders simultaneously and analyzing the image, all configuration errorsmay be detected and indicated to the operator in one turn, which is agreat advantage as compared with those machines, where a successivescanning of the feeders is performed as explained in connection with theaforementioned Japanese system by Tsunoda.

The equipment necessary for post-mounting a system according to theinvention, where the method according to the invention may beimplemented, is cheap and implies mainly one or several low costcameras, some cabling, a programmed computer and an image analysisprogram. Therefore, such a system is highly attractive. Anotheradvantage is the fact that the method according to the invention isapplicable for several types of machines. It may be applied withmachines, where the feeder slots are mounted on a stationary platformand where the components are picked-up by a moving pick-up. It may alsobe applied for machines, where the pick-up is stationary and where theplatform with the feeder slots is displaceable.

With the method according to the invention, manual checking proceduresare avoided, reducing mistakes by operators and therefore reducesmachine stopping during operation.

The method steps may be used before the machine starts operating alreadyduring the mount of feeders into the slots. Thus, once all feeders areinstalled, the check has already been finished and the placement machinemay start operation immediately. In contrast to the method as disclosedin the aforementioned Japanese patent application JP 2000 0223923 byAkira Tsunoda, no time consuming scanning with movable hardwarecomponents is required after the installation of the feeders. Accordingto the invention, a single image may be processed revealing within shorttime, whether mistakes have been made during the mounting process.

The saved time as compared to the Japanese system by Tsunoda can beestimated to the range of 10-30 seconds for each scan, which does notseem much at first sight. However, it has to be stressed that thisamount of time is saved each time a wrong feeders is detected, and eachtime a feeder is changed, for example, when a feeder runs empty, or whenfailures are observed during operation or when the machine is stoppedfor other reasons. This implies that, in total, a substantial amount oftime is gained by the invention in comparison to the Tsunoda system andother known systems. Especially, for articles where earnings are low,for example telephones, a high production speed is essential and asaving of time of only a few percent becomes crucial.

In order to assure a fast check and a high safety, the steps in themethod according to the invention may be repeated continuously beforestart of operation of the machine, for example during mount of thefeeders, such that the system may indicate acceptance of all feeders assoon as the feeders are installed and operation may start immediately.Thus, the time used for check is optimized in this way. Furthermore, itmay be repeated continuously during operation of the machine in order toprovide additional safety.

The intended feeder ID refers to the expected feeder to be found in theactual slot according to stored configuration information, while theactual feeder ID refers to the feeder which actually is in the actualslot. These two IDs are compared, and in case of discrepancy between theintended feeder ID and the actual feeder ID, the discrepancy may beindicated, for example by an alert to the operator of the machine, orstored and evaluated by other means.

Whilst the feeder ID is actually indicated on the feeder and used forreading, the slot ID need not be indicated on the slot itself. However,the slot ID is unique and stored in a database as an address forcomponent pick-up from the corresponding slot. Such slot ID may compriseor be linked to a relative position of the feeder.

Preferably, the stored configuration information comprises a first list,a Feeder/Component List, associating each intended feeder ID with acomponent ID indicative of the type of component to be contained in thecorresponding feeder, and a second list, Device List, associating feederslots IDs (208) with component IDs. These data lists are normallyavailable, as these lists are used in the programmed operation of themachine.

As many different types of feeders exist, even for the same machinetype, it might be difficult to place the feeder identifier exactly onthe same position on every feeder. Most likely the feeder identifierwill be placed in different positions on different feeder types. This istaken into account in a further embodiment, wherein the method furthercomprises the following steps in connection with mount of a componentreel in a feeder; imaging the feeder ID of the feeder with a furthercamera, calculating data indicative for the position of the feeder IDrelative to a reference point related to the feeder, and storing in adatabase the data for use as configuration information. Thus, theinvention does allow some offset on the feeder identifier position onthe feeder. According to the invention, this is taken into account byregistration of the offset in a so-called kitting station, into whichthe feeder is placed and where the feeder ID and the position of thefeeder ID are read with the camera. Then, the offset is calculated intwo dimensions as the position of the feeder identifier compared to afixed reference point. The offset for the feeder ID is then saved in thedatabase for later use as configuration information which may be usedfor calibration. Therefore, the demands of the invention are by far lessstringent than existing systems, which makes the method and systemaccording to the invention much more flexible.

The different feeder slots are in most known systems positioned withequal distances. However, for the method and system according to theinvention, this is not necessary as the invention in a furtherembodiment foresees a calibration procedure of the slot positions. Thiscalibration provides a series of position coordinates which afterwardsmay be associated to a slot ID of a feeder slot in the series of feederslots.

Such a calibration has a further advantage. Even though the slotpositions on a feeder station may be distributed with exactly the samedistance between every position, this may appear not to be the case onthe image taken by the camera. Depending on the type of camera lens, theimage may be distorted so that the slot distance in the edge of theimage seems to be larger than in the centre of the image. Therefore, thesystem is advantageously calibrated with position data describing thecoordinate of every slot position in the camera image.

A calibration of this kind may be performed by using a specialcalibration feeder mounted with a feeder identifier containing a specialfeeder ID that can be recognized by the system. The calibration feederis then placed slot by slot in all slot positions on the feeder station,and for every position, the system is instructed about the slot number,for example via a keyboard. The system can then save the calibrationdata containing position coordinates for each slot position.

A further development of this calibration method consists of having aspecial calibration feeder with two or maybe more—feeder IDs. Thesefeeder IDs are placed with a distance that is exactly the same as thedistance between slot positions on the feeder station. Then two slotpositions can be calibrated every time the feeder is placed in a slotduring the calibration procedure, and thus the calibration procedure isfast.

An even further development of the calibration method is to place thecalibration feeder with two (or more) feeder identifiers only in a slotin the centre of the camera image and in a slot at the edge of thecamera image. Then by measuring the distance between slots in the centreof the image and at the edge of the image, the calibration data for theremaining slots within the camera image can be approximated by assumingthat the slot distance changes linearly or parabolic from the centre tothe edge of the image.

An alternative calibration method is the following; if the slot distancebetween adjacent slots in the series of feeder slots is assumed to beconstant. In this case the calibration for associating positioncoordinates to the slot ID of each feeder slot comprises determining foreach particular feeder slot the number of slots from the first slot tothe particular feeder slot, and adding to the position coordinate of thefirst slot coordinates equivalent to the distance from the first slot tothe particular feeder slot, where this distance is calculated as theslot distance between adjacent slots times the number of slots from thefirst slot to the particular feeder slot. This is a very simpleprocedure which is safe and fast.

For this method, it is of advantage, if the calibration for associatingposition coordinates to the slot ID of each feeder slot comprises theprovision of a position mark with a certain fixed distance to the seriesof feeder slots, such that imaging the position mark together with theseries of feeder slots may be used for calculating the positioncoordinates in relation to the position mark. The value of this step maybe recognized by the following. The platform may be of the movable type,where the rest position or start position of the platform is not welldefined or sufficient accurate. In these cases, it is of advantage thatthe image analysis program may recognize a position mark by which thecoordinates of the slots with feeders may easily be calculated.Advantages of a position mark may also be apparent, if the camera duringoperation is exposed to dust, such that the image analysis program maynot function properly any more and the first slot is not determinablewith certainty. Equal difficulty may also arise in case that the camerahas been moved accidentally.

In case that the series of feeder slots are mounted on a displaceableplatform with a predetermined, sufficiently well-defined rest positionor predetermined start position, the calibration for associatingposition coordinates to the slot ID may be performed using an imagetaken in the rest position or start position of the platform.

Such a calibration is advantageously used together with a further step,where an actual position coordinate is assigned to each of the actualfeeder IDs in order to associate each actual feeder ID to a respectiveslot ID.

In a certain embodiment of the invention, the check for configurationerrors comprises determining from stored configuration information theintended feeder IDs of those feeders that are intended to be installedin respective slots in the series of feeder slots and checking bycomparing the actual feeder IDs with the intended feeder IDs in therespective slots, whether the actually installed feeders in the feederslots correspond to the intended feeders, and if this is not the case,indicating this discrepancy. This embodiment may be illustrated in moredetail by the following practical approach.

In connection with the image of the series of feeder slots, a series ofposition coordinates is provided, where each position coordinate isassociated to a slot ID of a feeder slot in this series of feeder slots.These position coordinates may be given for all slots or only for thoseslots where feeders are installed and used for the component pick-up. Byperforming image analysis of the obtained image, the actual feeder IDsof the actually installed feeders in the series of feeder slots aredetermined and an actual position coordinate is assigned to each ofthese actual feeder IDs. Such an actual position coordinate is takenfrom the series of position coordinates. From stored configurationinformation, typically the Device List and the Feeder/Component List,the intended feeder IDs are determined of those feeders that areintended to be installed in the series of feeder slots. Furthermore, foreach of those intended feeders, an intended position coordinate isdetermined, which also is taken from the series of position coordinates.

Then, for each intended position coordinate, it is checked whether anactual feeder ID is assigned to the position, and if this is not thecase, this is indicated, for example by an alarm message to the operatorof the machine. If on the other hand this is the case, it is checkedwhether the intended feeder ID and the actual feeder ID for thisposition coordinate are equal, and if this is not the case, thisdiscrepancy is indicated, for example by an alert to the operator.

In this practical approach, the intermediate step has been assumed thatthe method further comprises determining for each of those intendedfeeders an intended position coordinate, the intended positioncoordinate taken from the series of position coordinates, and checkingfor each intended position coordinate, whether an actual feeder ID isassigned to the position, and indicating if this is not the case.

Instead of comparing the intended ID of the intended feeders in theseries of slots with the imaged actual feeder ID's, as described in theforegoing, an alternative embodiment may be used, where intendedcomponents are compared to actual components. This embodiment is inprinciple equivalent to the foregoing though in practice slightlydifferent. This alternative embodiment comprises for each actual feeder,determining from stored configuration information a first component IDfor the type of components actually contained in the actual feeder,where the stored configuration information comprises a first listassociating each intended feeder ID with a component ID indicative ofthe type of component to be contained in the corresponding feeder, foreach slot defined to contain a feeder, determining from storedconfiguration information the second component ID for the component thatis supposed to be contained in a feeder in the slot, where the storedconfiguration information comprises a second list associating feederslots with component IDs, and checking whether the first and the secondcomponent ID are equal, and if this is not the case, indicating thisdiscrepancy.

Measuring distances and assigning coordinates to the slots and feederscan be used for a further improvement of the invention. In this case,the feeder type may be identified, for example by measuring the width ofthe feeder. This feature further reduces the risk for faults.

The following embodiment of the invention takes into account thesituation of splicing in certain placement machines. Splicing isperformed manually, which due to human error may result in finalproducts having defects because wrong component reels have been splicedand packed into the feeder. In order to trace the wrong components fromthe wrong spliced reel, the invention foresees the following furtherembodiment. The splicing may be performed by incorporating a label, forexample a colored or patterned band behind the components at thesplicing region of the component reel in a feeder. The label is thenrecognized by the image analysis system and the date and time for theuse of components from a spliced reel may be stored in a database. If adefect product is found at a later stage and the quality control revealsa wrong component, the stored date and time data help finding otherdefect products.

In fact, the image system with the camera and the image analysis programmay be configured with such a resolution and precision that thecomponents to be picked-up from the feeders may be recognized by theimage analysis system for determination whether the components from afeeder in a feeder slot correspond to components intended to be takenfrom that feeder. In this case, a splicing of reels with wrongcomponents may be recognized early and the production of defect productsprevented.

In order to generally assure that the camera works properly, for exampleto assure that the CCD chip or the objective have not been subject todamage or that the cabling or image processing program work properly, animage control is preferably performed automatically for determining theperformance of the camera. For example such a control may be performedroutinely before every production process when the machine is stopped.Such a control may advantageously be combined with the aforementionedposition mark.

The pitch of the reel in a feeder is adjustable. For example, thedistance of the components to be picked-up from the reel in the feedermay be 4 mm. If the pitch in the feeder is 8 mm, only every secondcomponent is picked-up from the reel. Such a mistake is hard torecognize by the operator, because the production process itself workscorrectly, just every second component is wasted. The method accordingto the invention with the image system is taking account for thisproblem in a further embodiment, where the obtained image is analyzedfor recognition of the correct reel pitch. In case that the recognizedreel pitch is not in accordance with stored configuration information,an alert is given to the operator.

Furthermore, the image analysis program may as well be configured torecognize defect feeders installed in feeder slots.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail with reference to thedrawing, where

FIG. 1 shows the principle of a placement machine post-equipped with acamera,

FIG. 2 illustrates the method according to the invention,

FIG. 3 illustrates an alternative embodiment.

DESCRIPTION OF PREFERRED EMBODIMENT

In FIG. 1, a placement machine 101 is illustrated having a platform 102,on which a number of slots 103 are located. Into each slot 103, a feeder104 may be placed. Certain feeder 104 types may extend into severalslots 103. The platform 102 is displaced relatively to the componentpick up arm 105 for picking up components from different slots 103.Alternatively, the pick up arm 105 may be displaced with respect to theplatform 102.

Each feeder 104 is provided with an identification marker, feeder ID,for example a bar code label that is designed to be readable by anappropriate scanner. According to the invention, the feeder ID is imagedby a camera 107 and analyzed in a computer 108 by an image analysiscomputer program. By using a camera 107 according to the invention, thefeeder marker may be different from a bar-code and may containadditional information about the feeder, and eventually informationabout the contained type of components.

The camera 107 images the series of slots 103 with feeders on theplatform 102. The camera 107 may be equipped with an objective 109 witha view 110 that covers the complete platform 102. Alternatively to covera long platform 102, a number of cameras 107 may be used to take imageswhich then are combined by appropriate computer routines in the computer108.

For stationary platforms 102, the camera 107 may be mounted at a fixedposition. For moving platforms, the camera may move along with theplatform 102. Alternatively, the camera 107 and the image analysisprogram may be programmed only to evaluate images, when the platform 102is in a special position, for example the start position. For additionalprecision and convenience, a position mark 111 may be provided with afixed distance to the slots 103, for example by a mark 111 rigidlyconnected to the platform 102. In the latter case, the platform 102needs not to have a certain position for the imaging, as the positionmark 111 may have the role for coordinate calibration for the slots 103.Alternatively, the mark 111 may be positioned independently of theplatform 102. In case of a moving platform 102, the distance is notfixed but nevertheless well defined when the platform 102 is in the restor start position.

Normally, when component reels are loaded into a feeder 104, this isdone in a so-called kitting station where the feeder marker is read andthe feeder ID 203 is stored in a first list together with the firstcomponent ID 204′ of the component reel in the feeder 104. The computer108 is configured to have access to these data in a list, which isillustrated in FIG. 2 as a Feeder/Component List 201. From other storedconfiguration information, which is a second list shown as a Device List207, a second component ID 204 of the type of component expected in aslot with slot ID 208 may be found. Combining the data from these twolists 201, 207, the intended feeder with intended feeder ID 203—FeedN—in a certain feeder slot 208 may be found 212. Not all slots 103 maycontain a feeder 104, as not all slots 103 may have to be used in aproduction process. Link of the feeders from the Feeder/Component Listto the slots in the Device List is made through the measured positionsof the slots during calibration and the positions assigned to thefeeders by image analysis 205 performed on the images taken by thecamera.

In the computer program performing the method according to theinvention, the intended feeder ID 203 in each feeder containing slot ischecked against the actual feeder ID that has been read by the camerafor each particular slot. For this, the camera 107 images 202 theplatform 102, where each slot ID 208 is provided with positioncoordinates achieved by calibration. This is preferably done for allslots 103, such that a series of position coordinates is obtained forthe whole series of slots, but it may, alternatively, only be done forthose slots that are intended to contain feeders 103. The first slot isfound automatically by the image analysis 205, for example by using theposition mark 111, and a coordinate is assigned to this first slot. Incase that the distance between adjacent slots is constant for all slots103, the distance to the following slots can easily be found bymultiplication or addition and corresponding coordinates can be applied.If the distance between slots 103 is not constant, the image analysisprogram can be programmed to find the slots 103 automatically and thenassign appropriate position coordinates to the slots as determined fromthe image.

From the lists 201, 207 as described above, those slots 103 that containfeeders 104 are evaluated further in that it is checked 206 whether afeeder 104 is contained in theses slots 103 at all. If this is not thecase, an alert 209 is given to the operator. From the obtained image,the actual feeder marker is read and the actual feeder ID—FeedN′—determined 210. In a next step, the intended feeder ID—Feed N—and theactual feeder ID—Feed N′—are compared 211 and in case of non-compliance,an alert 209 is given to the operator.

Instead of comparing 211 the intended ID 203 of the intended feeders inthe series of slots 208 with the imaged actual feeder IDs 210, analternative embodiment may be used, which is in principle equivalentthough in practice slightly different. In FIG. 3, this alternativeapproach is illustrated. From the obtained image 202 which is analyzed205 in order to assign positions to the feeder IDs 203 for relatingtheses to the calibrated positions of the slots 208, the actual feeders104 in the slots 103 are determined 210. In this embodiment, the firstcomponent ID 204′ for the type of components contained in the actualfeeder 203 is determined from the Feeder/Component List 201. For eachslot 208 defined to contain a feeder, the second component ID 204 forthe component that is supposed to be contained in the slot 204 isdetermined from the device list 207. As a final step, it is checkedwhether the first and the second component ID are equal, and if this isnot the case, this discrepancy is indicated 209.

The alert 209 to the operator may alternatively be coupled to anautomatic stopping routine of the machine such that the control and theaction after a recognized fault may prevent any placement of components.The method according to the invention may be implemented to onlyfunction before the placement machine starts operating. It may also beimplemented such that the method is performed steadily during theoperation of the placement machine in order to achieve maximum security.

1. Method for component verification in connection with operation of a component placement machine (101) having a series of feeder slots (103) for holding component feeders (104) with feeder markers, each feeder marker carrying a unique feeder ID, wherein each feeder slot (103) has a unique slot ID (208), the method comprising determining (210) the actual feeder IDs carried by the actually installed feeders (104) in said series of feeder slots (103) and using this information in comparison with stored configuration information (201, 207) to check for configuration errors, characterized in that the method comprises providing at least one camera (107) for providing an image (202) spanning over said series of feeder slots (103), providing said image and performing image analysis (205) on it for determining (210) the actual feeder IDs carried by the actually installed feeders (104) in said series of feeder slots (103).
 2. Method according to claim 1, wherein said method steps are repeated continuously before start of operation of said machine, during operation of said machine, or both before start of operation and during operation of said machine.
 3. Method according to claim 1, wherein said stored configuration information comprises a first list (201) associating each intended feeder ID with a component ID (204′) indicative of the type of component to be contained in the corresponding feeder (203), and a second list (207) associating feeder slots IDs (208) with component IDs (204).
 4. Method according to claim 1, further comprising, in connection with mount of a component reel in a feeder, imaging the feeder ID of said feeder with a further camera, calculating data indicative for the position of said feeder ID relative to a reference point related to said feeder, and storing in a database said data for use as configuration information.
 5. Method according any of the claims 1, further comprising for the image analysis providing by calibration a series of position coordinates, where each position coordinate is associated to a slot ID (208) of a feeder slot (103) in said series of feeder slots, assigning an actual position coordinate to each of these actual feeder IDs and associating each actual feeder ID to a respective slot ID.
 6. Method according to claim 5, wherein the slot distance between adjacent slots (103) in said series of feeder slots is constant and wherein said calibration for associating position coordinates to the slot ID (208) of each feeder slot (103) comprises determining for each particular feeder slot (103) the number of slots from the first slot to the particular feeder slot, adding to the position coordinate of the first slot coordinates equivalent to the distance from the first slot to the particular feeder slot, where this distance is calculated as the slot distance between adjacent slots times the number of slots from the first slot to the particular feeder slot.
 7. Method according to claim 5, wherein said calibration for associating position coordinates to the slot ID (208) of each feeder slot (103) comprises providing a position mark (111) with a certain fixed distance to said series of feeder slots, imaging said position mark together with said series of feeder slots, and calculating the position coordinates in relation to said position mark.
 8. Method according to claim 6, wherein said series of feeder slots are mounted on a displaceable platform (102) with a predetermined rest position or predetermined start position, wherein said calibration for associating position coordinates to the slot ID is performed using an image taken in the rest position or start position of said platform (102).
 9. Method according to claim 1, wherein said check for configuration errors comprises determining (212) from stored configuration information (201, 207) the intended feeder IDs (203) of those feeders (104) that are intended to be installed in respective slots in said series of feeder slots (103), checking by comparing (211) the actual feeder IDs with the intended feeder IDs (203) in the respective slots, whether the actually installed feeders in the feeder slots correspond to the intended feeders, and if this is not the case, indicating (209) this discrepancy.
 10. Method according to claim 9, further comprising determining for each of those intended feeders an intended position coordinate, said intended position coordinate taken from said series of position coordinates, checking (206) for each intended position coordinate, whether an actual feeder ID is assigned to said position, and indicating (209) if this is not the case.
 11. Method according to claim 1, further comprising for each actual feeder, determining from stored configuration information (201) a first component ID (204′) for the type of components actually contained in said actual feeder, where said stored configuration information comprises a first list (201) associating each intended feeder ID with a component ID (204′) indicative of the type of component to be contained in the corresponding feeder (203), for each slot (208) defined to contain a feeder, determining from stored configuration information (207) the second component ID (204) for the component that is supposed to be contained in a feeder (104) in said slot (103), where said stored configuration information comprises a second list (207) associating feeder slots with component IDs, checking (213) whether the first (204′) and the second component ID (204) are equal, and if this is not the case, indicating (209) this discrepancy.
 12. Method according to claim 1, wherein the placement machine (101) is of the type where splicing is applicable, wherein the method further comprises image recognition of a label at the splicing region of the component reel in a feeder (104) and storing the data and time for the use of components from a spliced reel.
 13. Method according to claim 1, wherein the obtained image is analyzed for recognition of components from a feeder and for determination, whether the components from a feeder in a feeder slot corresponds to components intended to be taken from that feeder.
 14. Method according to claim 1, wherein the obtained image is analyzed for recognition of the reel pitch.
 15. System for a method according to claim 1, wherein the system comprises a component placement machine (101) having a series of feeder slots (103) for holding component feeders (104) with feeder markers, each feeder marker carrying a unique feeder ID, wherein each feeder slot (103) has a unique slot ID (208), characterized in that the system also comprises at least one digital camera (107) for providing a digital image (202) spanning over said series of feeder slots (103), an image analysis system functionally connected to said camera and being configured to perform image analysis (205) on said image for determining (210) the actual feeder IDs carried by the actually installed feeders (114) in said series of feeder slots (103), and a computer functionally connected to said image analysis system and configured to use the information determined by said image analysis system in comparison with stored configuration information (201, 207) to check for configuration errors. 